People have long dreamed of traveling to distant planets; the same issue has been covered in science fiction for over a century. In reality, there are many problems that prevent us from doing this, including the lack of adequate technologies. But this does not stop scientists from theorizing possible ways of conquering outer space, which may one day become quite real.
Ion engines
Ion Thrusters are unlikely to be new to Star Wars fans, since they were flown by the TIE Fighters. It is also a well-established technology used by the Dawn probe, launched in September 1997, to study the dwarf planets Vesta and Ceres.
Ion engines work when xenon atoms are bombarded with electrons to form ions. At the back of the engine are metal meshes, charged at 1000 volts, which fire ions at a tremendous speed. The thrust is quite small, but since space is a frictionless and zero gravity environment, it is constantly increasing. Dawn's top speed is 38,600 km / h.
Ion engines require minimal fuel. They are 10 times more efficient than chemical engines. They get their energy from large solar panels, so there is no need to build a fuel storage facility. It also gives ion thrusters, in theory, an inexhaustible source of energy.
The current problem with ion engines is that they are too slow to transport people. They could be used, for example, to transport equipment and supplies to the Martian colonies.
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Bussard ramjet
As mentioned above, one of the biggest challenges facing space travel is the amount of fuel needed. To solve this problem in the 1960s, it was proposed to create the so-called Bussard Interstellar Ramjet.
The idea is that the spacecraft picks up the protons scattered throughout the universe as it travels. If these protons can then be synthesized, the spacecraft is essentially flying a nuclear rocket.
True, there are a number of problems with the Ramjet concept. You can only raise a certain number of protons, and as the protons are picked up, significant resistance will also be born. In addition, there is a small question about creating a stable working nuclear fusion device.
Movement on a nuclear impulse
The idea of using nuclear power to launch spacecraft dates back to the 1950s. The Orion project was an initiative of NASA, which decided to build a ship the size of a nice skyscraper, launched from the explosion of a nuclear bomb underneath. You are already starting to guess about the problems associated with the project. To begin with, after this project, a huge amount of radiation should remain, and the astronauts themselves will receive radiation poisoning.
When the bomb explodes, it will create an electromagnetic pulse that will destroy the onboard electronics. And this if the launch is still successful and does not lead to fatal losses. The Orion project was considered primarily because it could get us to Mars in three months. An ordinary ship would take eighteen.
Obviously, Project Orion is dead, but the idea behind it lives on. Voyager 1, Voyager 2 and Cassini used a form of nuclear energy based on the decay of plutonium, converting it into electricity, for their flights. Unfortunately, the reserves of the necessary plutonium on our planet have come to an end, and it is quite difficult to start re-production, since it is a by-product of creating nuclear bombs.
Movement on laser beams
Aerospace engineer Leic Mirabeau came up with the idea of using laser motion in 1988 while working on the Star Wars missile defense project. The Mirabeau apparatus was supposed to be conical. A powerful laser beam would be fired from the narrow end of the cone containing the parabolic reflector.
This would heat the air inside to 30,000 degrees, leading to explosions that create thrust. Mirabeau believed that such a device would appear in the next 20 years, but his peers looked at this idea with skepticism.
Interstellar spacecraft "Daedalus"
The British Interplanetary Society has conducted research for five years, beginning in 1973, exploring the possibility of sending humans to Barnard's Star, which is six light years away. Their solution was the interplanetary spacecraft "Daedalus". Daedalus was a gigantic spacecraft, also the size of a good skyscraper, and would definitely be assembled in Earth orbit.
Like Project Orion, it had to use fusion engines. The fuel pellets would be injected at high speed into the reaction chamber, where beams of high-energy electrons would ignite them. The first stage was supposed to lift the Earth 46,000 tons of fuel, the second - a small part of the ship with 4,000 tons of fuel. The fuel was supposed to be helium-3.
Helium-3 is incredibly rare on Earth, but it is believed to be much more abundant on the Moon; it can also be found in cosmic clouds. Collecting the required amount would take 20 years. Helium-3 is also very difficult to ignite as a fuel as it requires a lot of heat. But if the project had burned out, the device would have accelerated to 12.2% of the speed of light and would have reached Barnard's Star in 50 years.
In 2009, research began under the Icarus project, which should show what interstellar travel can become after so many years of scientific progress.
Riding an asteroid
One of the biggest problems of space travel remains the impact of cosmic rays. If a person takes 1000 days to get to Mars, they will receive such radiation that the chances of developing cancer will rise from 1 to 19 percent.
The spacecraft is made of lightweight materials, and the radiation shields are too heavy. Therefore, a physics professor at the Massachusetts Institute of Technology believes that the best way to travel long distances is to land on an asteroid and create a tunnel under its surface.
The asteroid must be 10 meters wide and within several million kilometers of Earth and Mars for the plan to work. So far, five such asteroids are known, and all of them will pass near the Earth by 2100. The journey will be one-way, since there are no asteroids that fly back and forth. However, new discoveries are constantly taking place, therefore, perhaps we will find an asteroid flying from Mars to us at the right time.
Solar sail
Although the sails are hardly high-tech by today's standards, in the space context they received a good update. Instead of using the wind, these sails will use the energy of the sun. Solar sails will give the spacecraft little thrust, but since there is no friction in space, these sails will gradually pick up speed.
For example, a solar sail 400 meters wide can travel more than two billion kilometers a year. This is faster than a chemical-powered vessel can pass. It would also be cheaper.
Solar sail projects are also not uncommon. One from NASA is called Sunjammer, named after a short story by Arthur Clarke. The Sunjammer sail can be made of Kapton material and can be five microns thick, weigh less than 20 kilograms and when packaged can be as large as a washing machine.
Another variant, created in honor of Carl Sagan, should go into orbit very soon. There is also a theory that a solar sail could take a spacecraft to another solar system. Such a sail will be the size of a large city and its active center will be a powerful laser.
Magnetic sail
Most of the protons and electrons emitted from the Sun range from 400 to 600 kilometers per second. A magnetic sail could use their energy and push off from them. A loop of conductive material can produce a magnetic field that is perpendicular to the solar wind, and this will push the craft in the desired direction.
The problem is that the magnetic sail has to be 100 kilometers long. Technologies that will make it possible to make a sail from a superconducting material of this size and maintain the required temperature are simply not available now. Magnetic sails remain theory until the technology is developed.
Worm-hole
Originally from science fiction, wormholes have inspired people since their inception in theory in 1921. Although their existence is allowed, no direct evidence of this has yet been found. Wormholes are essentially tunnels in space through which an object, in theory, can pass. At the same time, wormholes are unstable - if someone wants to go through one of these, its walls can collapse.
For safe passage through the wormhole, the apparatus must use anti-gravity force. Physicists believe that we simply will not collect enough energy. If there is a wormhole through which people can pass, it is definitely not in nature; however, a sufficiently advanced civilization could build it. Therefore, until we meet or build it, the wormhole will remain a sci-fi fiction.
Warp Drive
Popularized by Star Trek, the idea of a warp drive allows you to travel literally faster than the speed of light without breaking the laws of physics. Nevertheless, scientists believe in the possibility of its implementation. Physicist Miguel Alcubierre first proposed the idea: create a spacecraft in the shape of a rugby ball with a flat ring around it. True, for the ship to fly, you need a ball of antimatter the size of Jupiter.
To make such a spacecraft possible, NASA's Harold White made changes to the project. In theory, his modified ship would require much less antimatter, on the order of 500 kilograms. He will be able to bend space-time and reach a speed 10 times faster than the speed of light. The journey to the nearest star will take four to five months.
Unfortunately, antimatter is extremely unstable. Just a third of a gram of antimatter can release as much energy as was released in the bombing of Hiroshima. Antimatter in White's project will be pulled by 1.5 million Hiroshima, which will be enough to destroy the Earth.